.NET Languages: List of .NET programming languages; resources. [DotNetPowered.com]
GotDotNet Resource Center: .Net Language Vendors: A listing of compiler vendors for .NET platform alternative languages.
MC# (MCSharp): A high-level object oriented programming language based on .NET Platform created specially for developing complex industrial program systems that could use multiprocessor architectures.
Nemerle: A hybrid (functional, object-oriented and imperative) programming language for the .NET platform. It is statically typed, has metaprogramming capabilities and is specifically designed for programmers with C#/Java background. [Open source, BSD-like license]